1. Field of the Disclosure
The present disclosure relates generally to image forming devices and more particularly to a trim bar entry geometry for a dual component development electrophotographic image forming device.
2. Description of the Related Art
Dual component development electrophotographic image forming devices include one or more reservoirs that store a mixture of toner and magnetic carrier beads (the “developer mix”). Toner is electrostatically attracted to the carrier beads as a result of triboelectric interaction between the toner and the carrier beads. A magnetic roll includes a stationary core having one or more permanent magnets and a sleeve that rotates around the core. The magnetic roll attracts the carrier beads in the reservoir having toner thereon to the outer surface of the sleeve through the use of magnetic fields from the core. A photoconductive drum in close proximity to the sleeve of the magnetic roll is charged by a charge roll to a predetermined voltage and a laser selectively discharges areas on the surface of the photoconductive drum to form a latent image on the surface of the photoconductive drum. The sleeve is electrically biased to facilitate the transfer of toner from the developer mix on the outer surface of the sleeve to the discharged areas on the surface of the photoconductive drum forming a toner image on the surface of the photoconductive drum. The photoconductive drum then transfers the toner image, directly or indirectly, to a media sheet forming a printed image on the media sheet.
As the developer mix on the outer surface of the sleeve approaches the photoconductive drum by rotation of the sleeve, the developer mix is trimmed to a desired mass on the magnetic roll by a trim bar. A gap between the trim bar and the outer surface of the sleeve (the “trim bar gap”) dictates how much developer mix is allowed to pass on the outer surface of the sleeve from the reservoir toward the photoconductive drum. The permanent magnet(s) include a pickup pole positioned upstream from the trim bar gap that magnetically attracts developer mix in the reservoir to the outer surface of the sleeve. A portion of the developer mix in the reservoir is positioned in a region of the reservoir between the pickup pole and the trim bar gap in proximity to the outer surface of the sleeve. This region of the reservoir is responsible for ensuring that an adequate amount of developer mix is available for transfer onto the outer surface of the sleeve in order to prevent print defects. This region of the reservoir is also responsible for a portion of the triboelectric charging of the toner through interaction between the toner and the carrier beads.